Wolff, a former Williams driver and wife to Mercedes chief Totto, has claimed that the remaining circuits do not suit her husband’s team’s cars.
Second-placed Vettel is currently 59-points behind Hamilton with four races to go.
But with 25 points awarded for pole position, it is looking highly unlikely the Brit will be caught.
Vettel has also failed to finish two of his last three races – pulling up on the fourth lap of the Japanese Grand Prix last weekend.
However, he will be able to take faith from Wolff’s comments as she explains her worries over Mercedes’ lead.
“Ferrari has a very fast car and I can imagine the title race remaining open until the end,” she told Sky Italia.
“In my view Vettel was just unlucky (in the last race)
“When you consider how far away Ferrari was last year, it’s been a great turnaround.
“It’s going to be very interesting because a couple of the circuits [coming up] are not Mercedes circuits, or will suit the Ferrari more.
“It’s not like last year where it’s quite clear what is going to happen so I think we’ll see a huge fight.”
Wolff also said that it is refreshing to see Hamilton racing against another manufacturer and not his own team mate, as had been with Nico Rosberg in recent years.
“Lewis is very relaxed this year, and you can see that he enjoys the fight with Ferrari,” she added.
“In the last years he was always against his teammate, which is always difficult. He’s in his best form now.”